| 0/0 |
2026/03/07 15:52 |
flow |
repro |
8m
Results: map[ReproOpts:{"procs":1,"repeat":true,"sandbox":"namespace","threaded":true,"collide":true} ReproSyz:r0 = openat$tun(0xffffffffffffff9c, &(0x7f0000000000)='/dev/net/tun\x00', 0x0, 0x0)
ioctl$TUNSETIFF(r0, 0x400454ca, &(0x7f0000000040)={'syz0\x00', 0x1002})
r1 = socket$inet_tcp(0x2, 0x1, 0x0)
ioctl$SIOCSIFFLAGS(r1, 0x8914, &(0x7f0000000080)={'syz0\x00', 0x1})
write(r0, &(0x7f00000000c0)={0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x45, 0x0, 0x0, 0x1c, 0x0, 0x0, 0x0, 0x0, 0x40, 0x11, 0x0, 0x0, 0xac, 0x14, 0x0, 0xaa, 0xac, 0x14, 0x0, 0xbb, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x0}, 0x2a) SyzkallerCommit:31e9c887f7dc24e04b3ca70d0d54fc34141844b0]
|
| 1/1 |
2026/03/07 15:52 |
action |
provide-var |
0m
Results: map[DescriptionFiles:[acpi_thermal_rel.txt aio.txt auto.txt binfmt.txt bpf.txt bpf_prog.txt bpf_trace.txt cgroup.txt damon.txt dev_ashmem.txt dev_bifrost.txt dev_binder.txt dev_binderfs.txt dev_block.txt dev_bsg.txt dev_bus_usb.txt dev_camx.txt dev_cdrom.txt dev_cec.txt dev_char_usb.txt dev_comedi.txt dev_dma_heap.txt dev_dri.txt dev_dsp.txt dev_dvb_demux.txt dev_dvb_dvr.txt dev_dvb_frontend.txt dev_fb.txt dev_floppy.txt dev_hidraw.txt dev_i2c.txt dev_i915.txt dev_img_rogue.txt dev_infiniband_rdma.txt dev_infiniband_rdma_cm.txt dev_input.txt dev_iommu.txt dev_kvm.txt dev_kvm_amd64.txt dev_kvm_arm64.txt dev_kvm_extra.txt dev_kvm_riscv64.txt dev_loop.txt dev_mali.txt dev_media.txt dev_msm.txt dev_msr.txt dev_nbd.txt dev_net_tun.txt dev_panthor.txt dev_ppp.txt dev_ptmx.txt dev_ptp.txt dev_qat_adf_ctl.txt dev_qrtr_tun.txt dev_random.txt dev_rfkill.txt dev_rtc.txt dev_sequencer.txt dev_sg.txt dev_snapshot.txt dev_snd_control.txt dev_snd_hw.txt dev_snd_midi.txt dev_snd_pcm.txt dev_snd_seq.txt dev_snd_timer.txt dev_sr.txt dev_sw_sync.txt dev_tlk_device.txt dev_trusty.txt dev_udmabuf.txt dev_uhid.txt dev_uinput.txt dev_usb_hiddev.txt dev_usbmon.txt dev_userio.txt dev_vfio.txt dev_vga_arbiter.txt dev_vhci.txt dev_video4linux.txt dev_video4linux_vim2m.txt dev_virtual_nci.txt dev_vtpm.txt fanotify.txt filesystem.txt fs_9p.txt fs_fuse.txt fs_incfs.txt fs_ioctl.txt fs_ioctl_autofs.txt fs_ioctl_btrfs.txt fs_ioctl_ext4.txt fs_ioctl_f2fs.txt fs_ioctl_fat.txt fs_ioctl_fscrypt.txt fs_ioctl_fsverity.txt fs_ioctl_xfs.txt futex.txt hafnium.txt inotify.txt io_uring.txt ipc.txt key.txt kfuzztest.txt l2cap.txt landlock.txt lsm.txt namespaces.txt net_80211.txt netfilter.txt netfilter_arp.txt netfilter_bridge.txt netfilter_ipv4.txt netfilter_ipv6.txt netfilter_ipvs.txt netfilter_targets.txt pagemap_ioctl.txt perf.txt prctl.txt quotactl.txt seccomp.txt security_apparmor.txt security_selinux.txt security_smack.txt socket.txt socket_alg.txt socket_ax25.txt socket_bluetooth.txt socket_caif.txt socket_can.txt socket_ieee802154.txt socket_inet.txt socket_inet6.txt socket_inet_dccp.txt socket_inet_icmp.txt socket_inet_igmp.txt socket_inet_l2tp.txt socket_inet_sctp.txt socket_inet_tcp.txt socket_inet_udp.txt socket_ip_tunnel.txt socket_isdn.txt socket_kcm.txt socket_key.txt socket_llc.txt socket_netlink.txt socket_netlink_audit.txt socket_netlink_crypto.txt socket_netlink_generic.txt socket_netlink_generic_80211.txt socket_netlink_generic_batadv.txt socket_netlink_generic_devlink.txt socket_netlink_generic_ethtool.txt socket_netlink_generic_fou.txt socket_netlink_generic_gtp.txt socket_netlink_generic_mptcp.txt socket_netlink_generic_net_dm.txt socket_netlink_generic_netlabel.txt socket_netlink_generic_nfc.txt socket_netlink_generic_seg6.txt socket_netlink_generic_smc.txt socket_netlink_generic_team.txt socket_netlink_generic_wireguard.txt socket_netlink_netfilter.txt socket_netlink_netfilter_acct.txt socket_netlink_netfilter_conntrack.txt socket_netlink_netfilter_conntrack_exp.txt socket_netlink_netfilter_conntrack_helper.txt socket_netlink_netfilter_ipset.txt socket_netlink_netfilter_log.txt socket_netlink_netfilter_nft_compat.txt socket_netlink_netfilter_nftables.txt socket_netlink_netfilter_osf.txt socket_netlink_netfilter_queue.txt socket_netlink_netfilter_timeout.txt socket_netlink_rdma.txt socket_netlink_route.txt socket_netlink_route_sched.txt socket_netlink_route_sched_retired.txt socket_netlink_sock_diag.txt socket_netlink_xfrm.txt socket_netrom.txt socket_nfc.txt socket_nvme_of_tcp.txt socket_packet.txt socket_phonet.txt socket_pppox.txt socket_qipcrtr.txt socket_rds.txt socket_rose.txt socket_rxrpc.txt socket_tipc.txt socket_tipc_netlink.txt socket_unix.txt socket_vnet.txt socket_x25.txt socket_xdp.txt sys.txt uffd.txt usbip.txt vmw_vmci.txt vnet.txt vnet_mptcp.txt vusb.txt watch_queue.txt xattr.txt] SyzkallerCommit:31e9c887f7dc24e04b3ca70d0d54fc34141844b0]
|
| 2/1 |
2026/03/07 15:52 |
action |
kernel-checkouter |
0m
Results: map[KernelSrc:/usr/local/google/home/dvyukov/syzkaller/agent/workdir/cache/src/68b1644a07167f990af784849cc844972ce3d502]
|
| 3/1 |
2026/03/07 15:53 |
action |
kernel-builder |
2m
Results: map[KernelObj:/usr/local/google/home/dvyukov/syzkaller/agent/workdir/cache/build/9f64d327bdbee13bf7acc7c336db5c02334eb278]
|
| 4/1 |
2026/03/07 15:56 |
agent |
crash-repro-finder |
4m
Model:
Results: map[ReproOpts:{"procs":1,"repeat":true,"sandbox":"namespace","threaded":true,"collide":true}]
Instruction:
You are an expert in linux kernel fuzzing. Your goal is to write a syzkaller program to trigger a specific bug.
Print only the syz program that could be executed directly, without backticks.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt:
Bug Title: kernel panic: corrupted stack end in do_idle
Original Crash Report:
Kernel panic - not syncing: corrupted stack end detected inside scheduler
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT
Tainted: [L]=SOFTLOCKUP
Hardware name: ARM-Versatile Express
Call trace:
[<80201a14>] (dump_backtrace) from [<80201b08>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
r7:8281f940 r6:00000000 r5:822a7804 r4:00000001
[<80201af0>] (show_stack) from [<8021e458>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201af0>] (show_stack) from [<8021e458>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120)
[<8021e3fc>] (dump_stack_lvl) from [<8021e484>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
r7:8281f940 r6:00000000 r5:8281b680 r4:82a80d14
[<8021e46c>] (dump_stack) from [<802025f4>] (vpanic+0x114/0x320 kernel/panic.c:650)
[<802024e0>] (vpanic) from [<80202834>] (trace_suspend_resume+0x0/0x104 kernel/panic.c:787)
r7:826cc400
[<80202800>] (panic) from [<81ae5584>] (schedule_debug kernel/sched/core.c:5855 [inline])
[<80202800>] (panic) from [<81ae5584>] (__schedule+0x13d8/0x13e0 kernel/sched/core.c:6783)
r3:57ac6e9d r2:8280001c r1:822a7804 r0:82298d68
[<81ae41ac>] (__schedule) from [<81ae57bc>] (schedule_idle+0x24/0x68 kernel/sched/core.c:7030)
r10:8281b0b4 r9:00000000 r8:00000000 r7:8280c590 r6:8281b680 r5:8280c550
r4:8281b680
[<81ae5798>] (schedule_idle) from [<802b2ee8>] (do_idle+0x17c/0x2f0 kernel/sched/idle.c:360)
r5:8280c550 r4:00000000
[<802b2d6c>] (do_idle) from [<802b336c>] (cpu_startup_entry+0x30/0x34 kernel/sched/idle.c:430)
r10:8281b0b4 r9:823d05fc r8:00000000 r7:dddf03ec r6:8280c500 r5:82822440
r4:000000ed
[<802b333c>] (cpu_startup_entry) from [<81ae2458>] (rest_init+0xdc/0xe0 init/main.c:760)
[<81ae237c>] (rest_init) from [<8260144c>] (start_kernel+0x824/0x840 init/main.c:1210)
[<82600c28>] (start_kernel) from [<00000000>] (0x0)
Rebooting in 86400 seconds..
The list of existing description files:
acpi_thermal_rel.txt
aio.txt
auto.txt
binfmt.txt
bpf.txt
bpf_prog.txt
bpf_trace.txt
cgroup.txt
damon.txt
dev_ashmem.txt
dev_bifrost.txt
dev_binder.txt
dev_binderfs.txt
dev_block.txt
dev_bsg.txt
dev_bus_usb.txt
dev_camx.txt
dev_cdrom.txt
dev_cec.txt
dev_char_usb.txt
dev_comedi.txt
dev_dma_heap.txt
dev_dri.txt
dev_dsp.txt
dev_dvb_demux.txt
dev_dvb_dvr.txt
dev_dvb_frontend.txt
dev_fb.txt
dev_floppy.txt
dev_hidraw.txt
dev_i2c.txt
dev_i915.txt
dev_img_rogue.txt
dev_infiniband_rdma.txt
dev_infiniband_rdma_cm.txt
dev_input.txt
dev_iommu.txt
dev_kvm.txt
dev_kvm_amd64.txt
dev_kvm_arm64.txt
dev_kvm_extra.txt
dev_kvm_riscv64.txt
dev_loop.txt
dev_mali.txt
dev_media.txt
dev_msm.txt
dev_msr.txt
dev_nbd.txt
dev_net_tun.txt
dev_panthor.txt
dev_ppp.txt
dev_ptmx.txt
dev_ptp.txt
dev_qat_adf_ctl.txt
dev_qrtr_tun.txt
dev_random.txt
dev_rfkill.txt
dev_rtc.txt
dev_sequencer.txt
dev_sg.txt
dev_snapshot.txt
dev_snd_control.txt
dev_snd_hw.txt
dev_snd_midi.txt
dev_snd_pcm.txt
dev_snd_seq.txt
dev_snd_timer.txt
dev_sr.txt
dev_sw_sync.txt
dev_tlk_device.txt
dev_trusty.txt
dev_udmabuf.txt
dev_uhid.txt
dev_uinput.txt
dev_usb_hiddev.txt
dev_usbmon.txt
dev_userio.txt
dev_vfio.txt
dev_vga_arbiter.txt
dev_vhci.txt
dev_video4linux.txt
dev_video4linux_vim2m.txt
dev_virtual_nci.txt
dev_vtpm.txt
fanotify.txt
filesystem.txt
fs_9p.txt
fs_fuse.txt
fs_incfs.txt
fs_ioctl.txt
fs_ioctl_autofs.txt
fs_ioctl_btrfs.txt
fs_ioctl_ext4.txt
fs_ioctl_f2fs.txt
fs_ioctl_fat.txt
fs_ioctl_fscrypt.txt
fs_ioctl_fsverity.txt
fs_ioctl_xfs.txt
futex.txt
hafnium.txt
inotify.txt
io_uring.txt
ipc.txt
key.txt
kfuzztest.txt
l2cap.txt
landlock.txt
lsm.txt
namespaces.txt
net_80211.txt
netfilter.txt
netfilter_arp.txt
netfilter_bridge.txt
netfilter_ipv4.txt
netfilter_ipv6.txt
netfilter_ipvs.txt
netfilter_targets.txt
pagemap_ioctl.txt
perf.txt
prctl.txt
quotactl.txt
seccomp.txt
security_apparmor.txt
security_selinux.txt
security_smack.txt
socket.txt
socket_alg.txt
socket_ax25.txt
socket_bluetooth.txt
socket_caif.txt
socket_can.txt
socket_ieee802154.txt
socket_inet.txt
socket_inet6.txt
socket_inet_dccp.txt
socket_inet_icmp.txt
socket_inet_igmp.txt
socket_inet_l2tp.txt
socket_inet_sctp.txt
socket_inet_tcp.txt
socket_inet_udp.txt
socket_ip_tunnel.txt
socket_isdn.txt
socket_kcm.txt
socket_key.txt
socket_llc.txt
socket_netlink.txt
socket_netlink_audit.txt
socket_netlink_crypto.txt
socket_netlink_generic.txt
socket_netlink_generic_80211.txt
socket_netlink_generic_batadv.txt
socket_netlink_generic_devlink.txt
socket_netlink_generic_ethtool.txt
socket_netlink_generic_fou.txt
socket_netlink_generic_gtp.txt
socket_netlink_generic_mptcp.txt
socket_netlink_generic_net_dm.txt
socket_netlink_generic_netlabel.txt
socket_netlink_generic_nfc.txt
socket_netlink_generic_seg6.txt
socket_netlink_generic_smc.txt
socket_netlink_generic_team.txt
socket_netlink_generic_wireguard.txt
socket_netlink_netfilter.txt
socket_netlink_netfilter_acct.txt
socket_netlink_netfilter_conntrack.txt
socket_netlink_netfilter_conntrack_exp.txt
socket_netlink_netfilter_conntrack_helper.txt
socket_netlink_netfilter_ipset.txt
socket_netlink_netfilter_log.txt
socket_netlink_netfilter_nft_compat.txt
socket_netlink_netfilter_nftables.txt
socket_netlink_netfilter_osf.txt
socket_netlink_netfilter_queue.txt
socket_netlink_netfilter_timeout.txt
socket_netlink_rdma.txt
socket_netlink_route.txt
socket_netlink_route_sched.txt
socket_netlink_route_sched_retired.txt
socket_netlink_sock_diag.txt
socket_netlink_xfrm.txt
socket_netrom.txt
socket_nfc.txt
socket_nvme_of_tcp.txt
socket_packet.txt
socket_phonet.txt
socket_pppox.txt
socket_qipcrtr.txt
socket_rds.txt
socket_rose.txt
socket_rxrpc.txt
socket_tipc.txt
socket_tipc_netlink.txt
socket_unix.txt
socket_vnet.txt
socket_x25.txt
socket_xdp.txt
sys.txt
uffd.txt
usbip.txt
vmw_vmci.txt
vnet.txt
vnet_mptcp.txt
vusb.txt
watch_queue.txt
xattr.txt
Reply: r0 = openat$tun(0xffffffffffffff9c, &(0x7f0000000000)='/dev/net/tun\x00', 0x0, 0x0)
ioctl$TUNSETIFF(r0, 0x400454ca, &(0x7f0000000040)={'syz0\x00', 0x1002})
r1 = socket$inet_tcp(0x2, 0x1, 0x0)
ioctl$SIOCSIFFLAGS(r1, 0x8914, &(0x7f0000000080)={'syz0\x00', 0x1})
write(r0, &(0x7f00000000c0)={0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x45, 0x0, 0x0, 0x1c, 0x0, 0x0, 0x0, 0x0, 0x40, 0x11, 0x0, 0x0, 0xac, 0x14, 0x0, 0xaa, 0xac, 0x14, 0x0, 0xbb, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x0}, 0x2a)
|
| 5/2 |
2026/03/07 15:56 |
llm |
crash-repro-finder |
3m
Model:
Tokens:
input: 3000
output: 39
thoughts: 10776
Thoughts: **Analysis of Syzkaller-Triggered Kernel Panic: "corrupted stack end in do_idle"**
Okay, here's the breakdown. The goal is to craft a syzkaller program that reliably triggers a "corrupted stack end in do_idle" kernel panic on ARM 32-bit (Versatile Express) hardware. The crash report pinpoints the issue within the scheduler's `schedule_debug` function, specifically during the idle loop (`swapper/0`). The primary suspect is stack corruption, likely from a stack overflow or a write beyond the stack's bounds, which the scheduler detects via a stack canary or similar mechanism. This is unusual as syscalls generally trigger panics in their own context.
Given the idle task context, the corruption *must* be caused by either interrupt or softirq execution. The "Tainted: [L]=SOFTLOCKUP" further suggests the system might have been under some load or that a softlockup detector fired. Syzkaller's file lists include BPF, networking, and socket descriptions. This points us to potentially trigger deep stack usage in interrupt or softirq context, since it happened during an idle cycle.
Common causes are:
* BPF programs – with recursive calls or large stack frames, as they are often associated with interrupts and softirqs.
* Deeply nested networking packets – while typically limited, could still be a cause, especially if GRO or GSO are involved.
* Recursive filesystem calls – less likely here.
* Specific device drivers – not directly indicated here, but always a possibility.
The idle task's stack (which is the primary stack for the CPU) could be corrupted either during the execution of the idle loop itself (unlikely due to limited stack usage in idle) or during an interrupt or softirq. Since syzkaller is a syscall based fuzzer, we need to create a syscall chain that sets up an interrupt/softirq with heavy stack usage.
My thinking is: Without a precise reproducer (which I don't have), the best approach is to target a likely suspect: **networking**. Specifically, I'll focus on triggering potentially deep call chains. `tun` interfaces provide a nice way to inject packets into the network stack from userspace. `bpf` is in the list, but it's hard to write one from scratch, so, I will stick to `tun`.
Here's the planned approach: Set up a `tun` interface, bring it up, and then inject packets into it. This will invoke the network stack to handle the packets. Since the crash is stack corruption in the idle task, it suggests the softirq processing (NET\_RX\_SOFTIRQ) for the packets overflowed the stack *while* the CPU was idle. The packet will be crafted to cause more stack usage. The best strategy is often to inject traffic on the tun device that triggers GRO or GSO.
Here's the resulting `syz` program:
```
r0 = openat$tun(0xffffffffffffff9c, &(0x7f0000000000)='/dev/net/tun\x00', 0x0, 0x0)
ioctl$TUNSETIFF(r0, 0x400454ca, &(0x7f0000000040)={'syz0\x00', 0x1002})
r1 = socket$inet_tcp(0x2, 0x1, 0x0)
ioctl$SIOCSIFFLAGS(r1, 0x8914, &(0x7f0000000080)={'syz0\x00', 0x1})
write(r0, &(0x7f00000000c0)={0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x45, 0x0, 0x0, 0x1c, 0x0, 0x0, 0x0, 0x0, 0x40, 0x11, 0x0, 0x0, 0xac, 0x14, 0x0, 0xaa, 0xac, 0x14, 0x0, 0xbb, 0x0, 0x0, 0x
|
| 6/2 |
2026/03/07 16:00 |
tool |
set-results |
0m
Args: map[ReproOpts:{"procs":1,"repeat":true,"sandbox":"namespace","threaded":true,"collide":true}]
Results: map[ReproOpts:{"procs":1,"repeat":true,"sandbox":"namespace","threaded":true,"collide":true}]
|
| 7/2 |
2026/03/07 16:00 |
llm |
crash-repro-finder |
0m
Model:
Tokens:
input: 14877
output: 419
thoughts: 2046
Thoughts: **Syz Program Construction and Verification**
Okay, so the goal is to generate a syz program. I need to make sure the program is syntactically and semantically correct, targeting network stack issues via `tun` device injection. First, let's start with the base program structure. The program will open a `tun` interface and inject a crafted packet into it. The injected packet is a minimal UDP packet with all broadcast destination address.
The structure of the injected packet is:
- Ethernet Header: Destination (broadcast), Source (zeroed), and IPv4 type.
- IPv4 Header: Version, Length, UDP protocol, Source IP (172.20.0.170), Destination IP (172.20.0.187).
- UDP Header: Source and Destination ports (zeroed) and length.
Here's the planned syz program, where `r0` is the `tun` file descriptor, and `r1` is the socket file descriptor:
```
r0 = openat$tun(0xffffffffffffff9c, &(0x7f0000000000)='/dev/net/tun\x00', 0x0, 0x0)
ioctl$TUNSETIFF(r0, 0x400454ca, &(0x7f0000000040)={'syz0\x00', 0x1002})
r1 = socket$inet_tcp(0x2, 0x1, 0x0)
ioctl$SIOCSIFFLAGS(r1, 0x8914, &(0x7f0000000080)={'syz0\x00', 0x1})
write(r0, &(0x7f00000000c0)={0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x45, 0x0, 0x0, 0x1c, 0x0, 0x0, 0x0, 0x0, 0x40, 0x11, 0x0, 0x0, 0xac, 0x14, 0x0, 0xaa, 0xac, 0x14, 0x0, 0xbb, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x0}, 0x2a)
```
Now to verify each step: The most critical one is the `ioctl` with the specific numbers. Specifically, is `0x400454ca` the correct value for `TUNSETIFF`? Usually, it's correct for 32-bit archs that uses little endian for integers, but the syzkaller will ideally fetch that value depending on target architecture and the definition on the target kernel. But it looks correct. The target could be ARM 32-bit. The `TUNSETIFF` ioctl takes `struct ifreq` or a pointer to `struct ifreq`, which I believe is handled correctly in the provided context for syz. The value `0x400454ca` should be correct, based on my understanding of `_IOW` and Linux kernel definitions. The other `ioctl` number, `SIOCSIFFLAGS` (0x8914), is a standard value and should be universally valid. I'll make sure to double check that.
The socket call uses `inet_tcp`. I could use `inet_udp`, but the choice of socket type for ioctl doesn't really matter here. I can use `inet_tcp` for convenience.
Looking at the packet content, the IP addresses (172.20.0.170 and 172.20.0.187) are correct.
Finally, I will double check the registers, `r0` and `r1` usages in `write` and `ioctl`. It's fine.
One final sanity check, does the `openat$tun` system call exist? I will check the available syz calls, and it is there.
Okay, the program should be valid. Here is the final output.
```
r
|